Underground storage system



April 2, 1957 G. R. BENZ 2,787,125

UNDERGROUND STORAGE SYSTEM Filed Nov. 15, 1952 3 Sheets-Sheet lINVENTOR.

April 2, 1957 G. R. BENZ 2,787,125

UNDERGROUND STORAGE SYSTEM Filed -Nov. 13, 1952 3 Sheets-Sheet 2 IN V ENTOR.

(iJHBmz A ril 2, 1957 G. R. BENZ 2,787,125

UNDERGROUND STORAGE SYSTEM Filed Nov. 13, 1952 3 Sheeds-Sheet 3 PROPANEDETECTOR I JINVENTOR.

611?. Benz -D- 4 MM 3" M AT ORNEY pressure of the stored material in asafe manner.

:problem becomes extremely acute where it isnecessary oil-season.

limestone formations.

z,7s7,1 2s x UNDERGROUND STORAGE SYSTEM George R. Benz,Bartlesville,kla., assignor to Phillips Petroleum Company, a corporationof Delaware Application November 13, 1952, Serial No. 320,297 Claims.(CI. 61- 5 This invention relates to underground storage systems.

The constantly. expanding production of liquefied petroleum gashascreated a definite problem in providing suitable storage facilitiesfor this material. Due to the high vapor pressure of. liquefiedpetroleumgas, particularly 0 one, the cost of storage in surface equipment, suchas steel tanlas, becomes excessive due to the massive constructionrequired to withstandthe vapor This to store large quantities of suchmaterials during the in addition to the expense involved, the use ofsteel tanks is limited by shortages in production.

In order .toovercome these difficulties, it has been proposed to storeliquefied petroleum gas in porous water bearing formations, inwaterleached caverns in salt formations, or in abandoned mines in impermeableshale or Further, underground concrete storage tanks and buried sectionsof pipe have been used to a limited extent in the storage of liquefiedpetroleum 'In accordance with this invention, an underground storagesystem for liquefiedpetroleum gas is provided which is capable ofstoring'extremely large quantities of this material at a very small unitcost. Further, a number of operatin and safety features are providedtoinsure a long period of trouble-free operation of the storage system,easy and reliable introduction of the material storage facilities ofnovel construction and arrangement,

said facilities providing storage at a'minimum unit cost.

It is a further object toprovide a system in which the material can beeasily introduced into the storage system and removed therefrom.

It is a further object to provide a system in which the pumpingequipment, together withthe filling and dispensing lines, are readilyaccessible to workmen.

It is a still further object to provide an underground storage systemcapable of storing materials, such as propane, having a high vaporpressure for an'extended period with a minimum of operatingditficulties;

Various other objects, advantages and featuresof the invention willbecome apparent from the following detailed description taken inconjunction with theaccompanying drawings, in which:

Figure 1 is avertical sectional view,partially in elevation, of theunderground storage system of this invention;

Figure 2 is an enlarged horizontal sectional view of the tunnel system,looking downwardj Figure 3 is an enlarged vertical sectional view of thelower portion of the shaft showingthe equipment positioned therein; I

Figure 4 is a sectional view takenalong the, line 4 4 of Figure 3,looking in the direction of the f'arifows; and

barrier l4 resultsin an escape ofpropane vapors from .19. of a largeexcavated region, as illustrated in Figure 1,

170, Figure .2,

2,787,125 Pfatented J Apr. 2, 1 957 Figure 5 is a perspective view ofthe end of the filling and dispensing conduit.

Referring now to the drawings in detail, and particularly to Figure l,the underground storage system of this invention includes one or moreunderground storage caverns, one of which is indicated by referencenumeral it will be understood that each cavern can consist or,alternatively, the cavern can comprise a series of elongated individualstorage chambers of cylindrical or rectangular cross section with theaxis in a horizontal or vertical direction, as desired, all of thechambers defining the cavern communicating with a common, tunnel leadingto a central shaft in the manner'hereinafter explained.

A tunnel 11 connects the cavern 1 0 with an enlarged shaft 12extendingto the surface, and thebottom' region of the shaft preferablyextends a short distance below the floor of the tunnel, thereby defininga recess or well 13. It will be understood that, where a plurality ofcaverns are utilized, each cavern can be connected to the central shaftby a separate, preferably horizontal,

tunnel. One such additionaltunnel is indicated byreierence numeral liarand it .connected to a cavern llla in accordance with the invention,each tunnel incorporates a sealing structure, preferably disposed at theend of the tunnel remote from the shaft, to the end that liquid or vaporcannot leak from the caverns into the tunnels or shafts, even where thestored material is quite volatile and, therefore, develops a highvaporpressure. A suitable sealing structure is shown in connection withtunnel 11, this structure including asmassive elongated barrier or plug.14, preferably formedfrom poured concreteand disposedin the tunneladjacent its opening into thecavern. Spaced toward. the shaft from thebarrier. 14 is a second plug or barrier 15,.preferabiy formed frompoured concrete and substantially shorter than the barrier 14. In thismanner, a'chamber 16 isdefined intermediate the barriers 14, 15 whichcan be filled with water or other suitable liquid. Such liquid isintroduced into or removed from the chamber 16. by a pipe 17 or oneendltl of which eigtendsthrough thebarrier l5 and communi-cateswith thechamber 16, the other end of the pipe extending upwardly through theshaft, as indicated in Figure 3, to the. surface. p

, Preferably and advantageously, the liquid chamber to is water, anditis maintained under a pressure greater than that existing within thecavernitl to the end that any leakage which occurs through barrier 14:will. be leakage of water from the chamber 16 into the cavern ratherthan lealQa g-e ot propane or other stored material from the cavern intochamber, 16. IIlSGlllt. cases, the water or other liquid in chamberlo isnot pressurized and. the pipe 17 serves as a ventconnecting chamber ltiwith the surface. .Under such conditions, lealragemof propane throughthe barrier 14. will firstdisplace water and later propane from chamber16 and resultin an overflow of Water from the pipe 17 at the surface,which ser as as anindica-tion of such leakage. it will be understoodthat the chamber can either be filled with water or merely be filledwith air. .Where. air is present in the chambenjthe described leakage bfpropane through the enemas pipe 17 at the surface which, when detected,indicates such leakage. The surface equipment associated with pipe 17can, therefore, include a water storage tank 55,

a pump 56, a control valve 57, and/ or a propane analyzer tor detectors.

A large tubular conduit 20 extends through the barriers 14 and 15, oneend 21 of the conduit extending into and communicating with the cavernand the other end 22 of the conduit extending into the tunnel 11. Theend 22 of the conduit is closed and sealed by a flanged metal cap 23bolted thereto. The portion of the conduit 29 extending through barrier14 and, if desired through barrier is provided with a number of spacedfins or plates 24 which are embedded in the concrete or other materialmaking up the barriers. it will be evident that the conduit '20 permitsaccess to the cavern by a workman, and th fins embedded in the concreteare a material factor in preventing leakage of propane or other storedmaterial through the concrete barriers. The barrier 15 afiords anadditional sealing action, prevents water in chamber 16 from leakinginto the tunnel, and serves as a sealing barrier in the event of thefailure of barrier 14.

In further accordance with the invention, a filling and dispensing line25 extends through the barriers i4, 15 and has one end 26 thereofdisposed within the cavern 10. Preferably, the end part of the line iselevated, as by providing supports 27 beneath the line, and a slot 23 isprovided at the under side of the line. In this manner, fluids areeasily introduced into the line from the caverns or pass into the cavernthrough the line, and there is no tendency for the end of the pipe tobecome clogged by rocks or other debris accumulating at the bottom ofthe cavern. If desired, perforations can be provided in the end of theline, either to replace the slot 23 or in conjunction therewith, andadditional perforations can be provided as at 29 in a portion of theline which rests upon the floor of the cavern to allow removal ofresidual portions of stored material.

It will be noted that the line 25 is provided with a valve 30 in thetunnel adjacent barrier 15. The line 25 extends through a T connection31. to a valve 32 which, in turn, communicates with a line 25aincorporating a T connection 31a and a control valve 36a, the line 25abeing positioned within the tunnel 114:. It will be understood that theline 25a leads to another cavern lltla of the underground storagesystem, and that similar lines can be provided leading through suitabletunnels to a third, fourth, or greater number of caverns, as desired.Branching from the T connection 31 is a line 33 incorporating a Tconnection 34, a check valve 35, a pump 36, a check valve 37, and adispensing line 38 which extends upwardly through the shaft to thesurface where it is provided with a suitable valved connection 33mleading to liquid loading facilities or other outlet to which the storedmaterial is to be transferred. Branching from T connection 34 is afilling line 39 which, likewise, extends upwardly through the shaft 12to the surface where it is provided with a valved connection 39m to apump 3911, or other suitable device for introducing the material to bestored into the cavern. Assuming valve 32, Figure 2, to be closed andvalve 30 to be open, it Will be evident that material introduced throughfilling line 39 passes through line 33, Figure 4, T connection 31 andline 25 into the storage cavern, flow of liquid into the pump beingprevented by check valve 35. When the filling operation is completed,the up hole valve 39m in line 39 is closed and the material remains instorage. When pump 36 is actuated, material is withdrawn from the cavernthrough line 25, T connection 31, line 33, and check valve 35, andpassed by the pump through check valve 37 and dispensing line 38 to thesurface, it being understood that check valve 37 prevents reverse flowof liquid through the pump. Pump 36 can be actuated by an electric motorsupplied with power by suitableleads, not shown, extending upwardlythrough the shaft to the surface. Alternatively, any other suitableprime mover can be provided to operate the pump, such as an internalcombustion engine, the fumes being removed from the bottom of the shaftby the ventilating duct to be hereinafter described.

Further in accordance with the invention, a duplicate pumping andfilling system is associated with pipe 251:. This system comprises partscorresponding to elements 33 to 38, inclusive, and these parts areindicated by like reference numerals followed by the letter a. At thesur face, lines 3%, 3% are provided with valves 38p, 39p and. a. pinup3%: corresponding to valves 38m, 39m and pumps 3911, respectively. Withvalve 32 closed and valve 30a open, the filling and dispensingoperations are carried out in the manner already described to introducematerial to be stored into the cavern associated with tunnel flu or towithdraw material therefrom. It will be evident, however, that byopening valve 32 the filling and dispensing system 33 to 39 or 33a to 3%can be used in connection with both caverns simultaneously. Furthermore,by proper opening or closing of valves 3% and 30a, filling anddispensing system 330 to 39a can be used to introduce material into orwithdraw material from cavern .lii and, conversely, filling anddispensing system 33 to 39 can be used to introduce material into orwithdraw material from the cavern associated with tunnel 11a. Thepumping and dispensing systems are, therefore, completely flexible inthat each such system can be selectively used in connection with eithercavern or in connection with both caverns simultaneously.

As previously noted, it is an important object of the invention toprovide an underground storage system wherein the valves, pumps, andlines for introducing material into storage and Withdrawing materialtherefrom are readily accessible to workmen. To this end, theunderground storage system of this invention incorporates a hoist 45,Figure 1, which is suspended by a cable 46 and which is movablevertically within the shaft by mechanism including a hoisting motor andwinch 47, a derrick 48, and a sheave assembly 49. Since the shaft andthe lower parts of the tunnels are sealed off by the barriers 14, 15 soas to prevent presence of the stored material or its vapors therein, thehoist can be utilized to transport workmen to the tunnel levels whenadjustment of the valves is necessary, or when the pumps and otherstructure require maintenance work. The hoist mechanism can also be usedto raise or lower equipment such as pipe, pumps, and the like in theshaft. Furthermore, when all the stored material is withdrawn from thecavern, the vapors can be removed by the dispensing lines and pumps fromthe cavern 10, for example, and workmen can enter the cavern through theconduit 20 for purposes of inspection or maintenance.

Preferably and advantageously, I provide a vent duct 50 extendingdownwardly through the shaft 12 to a position adjacent the level of thetunnels, and air can be forced downwardly through this pipe by asuitable blower 50a at the surface. Alternatively, a pump can beprovided in conjunction with the line 50 to remove gases from the lowerpart of the shaft thereby drawing fresh air downwardly through the mainpart of the shaft. The latter procedure is particularly advantageouswhere the pumps 36, 36a are driven by internal combustion engines for,in this case, the exhaust products are readily removed through the ventpipe and proper ventilation of the lower part of the shaft and tunnelsis effected.

It will be apparent that I have obtained the objects of my invention inproviding an underground storage region or regions of very high capacityfor the storage of materials such as propane, the storage caverns beingsealed off so that access can be had to the pumping and dispensingsystem by workmen, the hoist and ventilating pipes cooperating to effectthis purpose. Furthermore, the dispensing and filling system is quiteadaptable in that either of the pumps can be utilized to pump liquidfrom either or both caverns during servicing or repair of the otherpump. It will be evident that the filling and dissary or desirable, andthe pipe 26 is so supported that there is no danger of its becomingclogged by debris accumulating at the floor of the cavern.

While the invention has been described in connection with a present,preferred embodiment thereof, it is to be understood that thisdescription is illustrative only and is not intended to limit theinvention.

This case is related to Serial No. 330,856, filed January 12, 1953, nowPatent No. 2,749,714 issued June 12, 1956.

I claim: 1. In an underground storage system, in combination,

an underground storage cavern, a shaft extending from the surface of theearth to a region adjacent said cavern,

a tunnel connecting said shaft with the bottom region of said cavern, abarrier "in said tunnel constructed and arranged to seal same againstthe flow of stored material frornjthe cavern to the shaft, a fluidWithdrawal and introduction pipeline extending from the shaft throughsaid tunnel and said barrier into said cavern, a T connection in saidpipeline adjacent the shaft, a control valve in said pipeline betweentheT connectionand said barrier, a filling conduit extending from said Tconnection upwardly through the shaft to the surface, and a dispensingsystem communicating with said T connection, said dispensing systemincluding a check valve preventing flow of fluid from said filling lineinto the dispensing system, a pump having its suction connected to saidcheck valve, and a dispensing conduit connected to the discharge of saidpump and extending upwardly through said shaft to the surface.

2. In an underground storage system, in combination, a pair ofunderground storage caverns, a shaft extending from the surface of theearth to a region adjacent said caverns, tunnels connecting said shaftwith the respec tive bottom regions of said caverns, a barrier disposedin each tunnel and constructed and arranged to prevent flow of storedmaterial from the cavern into the shaft, individual pipelines extendingfrom the shaft through the tunnels and barriers to the respectivestorage caverns, a common valve communicating with said pipelines, acontrol valve in each pipeline disposed between said common valve andthe associated barrier, and filling and dispensing systems connected tothe respective pipelines at a position between the common valve and thecontrol valve, each filling and dispensing system including a fillingconduit communicating with the pipeline, a check valve branching fromsaid filling conduit and disposed to prevent fluid flow from the fillingconduit therethrough, a pump having its suction connected to said checkvalve, and a dispensing conduit connected to the discharge of said pumpand extending upwardly through said shaft to the surface.

3. In an underground storage system, in combination, an undergroundstorage cavern, a shaft extending from the surface of the earth to aregion adjacent said cavern, a tunnel connecting said shaft with thebottom region of said cavern, a pair of spaced barriers in said tunnelextending across the entire cross sectional thereof so as to seal thetunnel against passage of stored material from said cavern, meansincluding a conduit extending from the shaft through both barriers tothe cavern for introducing material into the cavern and withdrawingmaterial therefrom, and a pipe extending through the barrier nearest theshaft and having one end thereof communicating with the region betweensaid barriers, said pipe extending upwardly through said shaft to thesurface.

4. In an underground storage system, in combination, a plurality ofunderground storage caverns, a shaft extending from the surface of theearth to a region adjacent all of said caverns, tunnels connecting saidshaft with the bottom regions of each of said caverns, a pair of spacedbarriers in each tunnel, each extending across the entire cross sectionthereof so as to seal the tunnel against passage of stored material fromsaid cavern, conduits extending from the shaft through the barriers intothe caverns for introducing material into thecaverns and withdrawingmaterial therefrom, and pipes extending through the barriers nearest theshaft, each pipe having one end opening into the region betweensaidbarriers and the other end extending upwardly through said shaft tothe surface. i

5. In an underground storage system, in combination. an undergroundstorage cavern, a shaft extending from the surface of the earth to aregion adjacent said cavern, a tunnel connecting said shaft with thebottom region of said cavern, a pair of spaced concrete barriers in saidtunnel, each extending across the entire cross sectional area thereof soas to seal the tunnel against passage of stored material from saidcavern,means including a con duit extending from the shaft through bothconcrete barriers to the cavern for introducing material into the cavernand withdrawing material therefrom, a pipe extending through theconcrete barrier nearest the shaft and having one end thereofcommunicating with the region be tween said barriers, said pipeextending upwardly through said shaft to the surface, an enlargedconduit extending through both barriers, one end of said enlargedconduit communicating with said cavern and the other end of saidenlarged conduit opening into said tunnel, said other end of theenlarged conduit having a cover plate secured thereto, and fins securedto said enlarged conduit and embedded in said concrete to improve thesealing action of the barrier.

6. In an underground storage system, in combination, an undergroundstorage cavern, a tunnel communicating with the bottom region of saidcavern, a pair of spaced concrete barriers in said tunnel adjacent saidcavern, said barriers being constructed and arranged so as to seal thetunnel and prevent passage of fluid from the cavern into the tunnel,filling and dispensing means for said cavern including a pipelineextending through the tunnel and both of said barriers into the cavern,and means for introducing fluid under pressure into the region of thetunnel bounded by said barriers, and fluid within said region at apressure greater than the cavern pressure so that any leakage occurringthrough the barrier adjacent said cavern is from said bounded regioninto the cavern.

7. In an underground storage system, in combination, an undergroundstorage cavern, a tunnel communicating with the bottom region of saidcavern, a pair of spaced concrete barriers in said tunnel adjacent saidcavern, said barriers being constructed and arranged so as to seal thetunnel and prevent passage of fluid from the cavern into the tunnel,filling and dispensing means for said cavern including a pipelineextending through the tunnel and both of said barriers into the cavern,means for introducing fluid under pressure into the region of the tunnelbounded by said barriers, and fluid within said region at a pressuregreater than the cavern pressure so that any leakage occurring throughthe barrier adjacent said cavcm is from said bounded region into thecavern, and an enlarged conduit extending from the tunnel through bothbarriers into the cavern, the end of said conduit within the tunnelbeing closed by a cover plate, and fins secured to the conduit andembedded in said concrete to improve the sealing action of saidbarriers.

8. In an underground storage system, in combination, an undergroundstorage cavern, a shaft extending from the surface of the earth to apoint adjacent said cavern, a tunnel connecting said shaft with the baseof said cavern, a pair of spaced fluid-tight barriers in said tunnelforming a chamber therein, a fluid stored within said cavern underpressure, another fluid occupying the chamber between the two barriers,said latter fluid being under a pressure greater than that of the fluidin the cavern to prevent leak- '3 age of the fluid in the cavernthrough-the barrier adjacent said cavern, means for admitting fiuids tosaid chamher and cavern, and means for Withdrawing fluid from saidcavernv 9. In an underground storage system in combination, anunderground storage cavern, a shaft extending from the surface of theearth to a point adjacent said cavern, a tunnel connecting said shaftwith said cavern, a pair of spaced concrete barriers in said tunnel,each sealing the tunnel from fluid flow therethrough, a fluid storedWithin said cavern under pressure, a liquid occupying the chantberbetween the two barriers, said liquid being under a pressure greaterthan that of the fluid in the cavern to prevent leakage from the latterto the tunnel, and a conduit extending from Within the chamber throughthe outer concrete barrier, tunnel, and shaft and terminating at a pointnear the surface of the shaft, said conduit being in open communicationwith the chamber and containing a column of the same liquid as that inthe chamber so that a change in pressure in said chamber is indicated bya change in liquid level in said conduit.

10. In an underground storage system in combination, an undergroundstorage cavern, a shaft extending from the surface of the earth to apoint adjacent said cavern, a tunnel connecting said shaft with saidcavern, a pair of 3 spaced fluid-tight barriers in said tunnel forming asealed chamber therein, a fluid stored within said cavern underpressure, a liquid occupying said chamber, a conduit extending fromWithin the chamber through the outer barrier, tunnel, and shaft andterminating at a point near the surface of the shaft, said conduit beingin open communication with the chamber, so that any substantial increasein pressure of the fluid in said cavern in excess of the pressure of theliquid in the chamber may be indicated by the escape of storage fluidfrom the top of said conduit.

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